Friction device.



PATENTED APR. 26, 1904.-

- GY.L.HARVEY.

FRICTION DEVICE.

APPLIOATION FILED DBO. 26. 1903.

a BHBETSBHEET 1,

N0 MODEL.

UNirnD STATES Patented April 26, 1904.

PATENT OFFICE.

FRICTION DEVICE.

SPECIFICATION forming part of Letters Patent No. 758,066, dated April 26, 1904.

Application filed December 26, 1903. Serial No, 186,544. (No model.) I I To all whom it may concern:

Be it known that I, GEORGE LYON HARVEY, a citizen of the United States, residing at Chicage, in the county of Cook and State of Illinois, (having a post-office address at 17 5 Dearborn street, Chicago, aforesaid) have invented certain new and useful Improvements in Friction Devices, of which the following is a full and true description, reference being had to the accompanying drawings, showing embodiments of my invention.

The object of this invention is the production of an exceedingly efficient and economical form of friction device especially useful as a compression-spring for draw-gear for railway-cars; and the improvements consist in the novel features and combinations hereinafter pointed out.

A distinctive feature of my present invention is the employment of inner and outer friction-springs of a novel construction.

A second feature is the providing of a friction-piece between the inner and outer members and taking up the friction.

A third feature of novelty is the employment of a series of short coils instead of a continuous long coil in either or both of the friction-springs; and a fourth feature of novelty is the employment of a device which prevents creeping of the elements of the friction device.

In the accompanying drawings, Figure 1 is an exterior view with the lower part broken away of one form of my invention. Fig. 2 is an exterior View of a friction device heretofore proposed, but embodying the third aboverecited feature of my invention. Fig. 3 is a longitudinal section of a structure made under my invention and employing three coiled members. Fig 4c is a sectional view of three loops of the inner and outer coils just brought together. Fig. 5 is a similar view showing modified forms of inner and outer members. Fig. 6 is a sectional view showing the loops of Fig. 4 fully compressed. Fig. 7 is a sectional view showing shape and arrangement of a modified form of device. Fig. 8 shows a figure similar to 4 with a friction member interposed between the loops. Fig. 9 shows an external view of one form of my friction device provided with a device which prevents creeping of the coils, and Fig. 10 is a longitudinal section showing more clearly the application ofsaid anticreeping device.

Referring to the illustrated forms of my new friction device, these essentially consist of in ner and outer members, both being coils, as distinguished from mere rings, As especially shown in Figs. 2 and 3, it is not necessary that either of said members shall be a single or continuous coil from end to end of the member. Either or both of the members may consist of a succession of short coils slightly out of contact, as B B B 2, or A A A", Fig. 3. Preferably both members shall be made of heavy bar metal with the adjacent friction contacting faces of the members substantially parallel and at an angle of forty-five degrees with respect to the axis of the friction device. Normally the adjacent coils of both members will be separated, as shown in Figs. 1 and 3, so that under'initial compression of the friction device there will be no engagement of the coils. As this compression is continued, however, the adjacent friction contacting faces of the coils come into frictional engagement, as clearly. shown in Figs. 4 and 5, with the result that upon the completion of the compression the outer coils, in addition to the.

longitudinal compression, are radially distort ed or expanded, whereby the yielding resistance to the load is increased.

By reference to Fig. 4 it will be seen that an imaginary line B intersects the center of each loop or spring of the coil B and marks the boundary-line of the loop or ring of the coil A, and by reference to Fig. 6 it will be seen that when the two springs are fully compressed the line B is no longer the boundary of the loop or ring of coil A, but said boundary is marked by a second imaginary line B. The difference between the lines B and B shows the relative distortional movements of the two springs A and B.

Referring now to Fig. 2, it will be seen that the spring A, which is made of square bar metal, is provided with sharp edges A and A It is obvious that when the device of Fig. 2 is fully compressed and the coils B have been sufiiciently distended to permit this to be done the sharp edges A and A l. will be brought together. At this stage of the op- (ration there is a great tendency of the successive loops or rings of A to slip or slide. past one another, due to the fact that twogsharp alined edges are in contact, and the spring will buckle or bend and is likely to be broken. The same would be true of a structure like that illustrated in Fig. 7 when the members B are provided with curved bearing-surfaces. Such a result is avoided by providing the loops with flattened surfaces B. I have overcome this defect by providing flattened upper and lower contact-faces on the loops or rings of either or both members. These flattened contact-faces are shown enlarged at B B, Fig. 4E, and the seating of two of them solidly together is shown in Fig. 6. Obviously when the two flattened faces come together, as shown in the last figure, the tendency to slide or slip will be greatly lessened as compared with the structures of Figs. 2 and 7, and when the several members of the friction device are each provided with flattened contact-faces the fullyloaded springs will seat like a solid tube,with little or no tendency to buckle or bend. As shown in Fig. 3, the friction device may have anouter coiled member O with flattened contact -faces, and this outer member will also contribute strength and elasticity to the friction device. As a further means of preventing buckling or bending the friction device may be housed in the draw-gear or provided with a cap. p

In Fig. 5 I have shown the bars of the inner and outer members as being made of hexagonal bars, the contact-faces B and A being quite broad. This form of spring gives increased bearingsurface,and the frictional contact-surfaces in engagement is very great, which means that the wear per square inch is reduced to a minimum.

In the forms of my invention already described the frictional engagement of the members A and B is direct. If desired, however, a friction member or plate may be interposed between said members, as shown in Fig. 8, wherein 1) represents a trough-shaped piece of friction metal fitted to the loops or rings A. The part D may be composed of one or more coils coincident with the coil or coils of the member A.

I have found that where a friction device is made up of inner and outer coiled springs there is a tendency for the springs to creep along from one end of the spring in relation vided means, one form of which is shown in Figs. 9 and 10 as applied to one form of my new friction device.

Broadly stated, the new anticreeping device consists of means which, while permitting compression of the inner and outer springs, as well as their distortion, prevents the two springs from winding or creeping along one another. One form of this device is shown in the drawings, wherein one or more corresponding grooves fit a' ribbed part. In the illustrated form X X represent V -shaped grooves cut in the inclined faces of adjamember and the expansion of the outer member the ribbed partY will slide in the grooves X without disengaging therefrom, and when the load is removed and the members return to normal position the grooves and rib will be still engaged, as shown in the drawings. This constant engagement of the parts referred to both when the friction device is at rest and when it is loaded prevents the creeping of one coil relatively to the other.

As shown in Fig. 1, the inner spring A may be longer than the outer spring or other' wise extended beyond the spring B in order that the spring A may be first put under compression.

I have hereinbefore spoken of making either or both of the members A or B of a succession of short coils. The same object may be accomplished by cutting the coils into sections.

What I claim is- 1. In a friction device, outer and inner coiled members, each consisting of a series of coils, which are normally separated and brought into frictional engagement with each other when one or both of the members are compressed, one of said members being flattened at its adjacent bearing-surfaces, substantially as described.

2. In a friction device, an inner coiled member consisting of a series of coils, said coils being flattened at their adjacent bearing-surfaces, and a surrounding coiled member normally separated from the inner member and having a frictional engagement therewith, substantially as described.

3. In a friction device, an inner coiled member consisting of a series of coils, said coils being flattened at their adjacent bearing-surfaces, and a surrounding coiled member of less sectional area, substantially as described.

i l i l l l l 4. In a friction device, outer and inner coiled members, one of which consists of a series of coils, which coils are flattened at their adjacent bearingsurfaces, and one of said members being of greater sectional area than the other coiled member, substantially as described.

5. In a friction device, outer and inner coiled members which are normally separated, one of said members being composed of a series of coils, substantially as described.

6. In a friction device, outer and inner coiled members which are normally separated, one of said members being composed of a series of connected coils, substantially as described.

7 In afriction device, outer and inner coiled members each consisting of a series of coils, said members being normally separated and brought into frictional engagement with each other when one or both of the members are compressed, one of said members extending beyond the other, substantially as described.

8. In a friction device, outer and inner normally separated coiled members, each consisting of a series of connected coils, one of the coiled members being of a greater sectional area than the other, substantially as described.

9. In afriction device, outer andinner coiled members, and a trough-shaped friction member located between the two coiled members, and secured to one of said members, and brought into frictional engagement with both when the device is compressed, substantially as described.

10. In a friction device, inner and outer coiled members, and a device for preventing the creeping of the members with relation to each other, substantially as described.

11. In a friction device, inner and outer coiled members, one of said members being grooved and the other member being ribbed, the engagement of the grooved and ribbed parts preventing the creeping of the members with relation to each other, substantially as described.

12. In a friction device, an inner member consisting of a series of coils which are flattened at their adjacent bearing-surfaces, and an outer member, normally separated from that first named, and also consisting of a series of coils which are flattened at their adjacent bearingsurfaces, substantially as described.

13. In a friction device, a mainspring consisting of a series of coils, provided with friction-surfaces inclined to the central axis of the spring and normally separated flat bearingsurfaces at approximately right angles to said axis, and a friction-spring operating against the mainspring and of lighter cross-section, substantially as described.

14. In a friction device, a spring member,

consisting of a series of coils provided with flat bearing-surfaces at angles to the central axis of the device, and a frictional element engaging the said spring member and normally separated therefrom, the friction-surfaces of the frictional element being at angles to the aforesaid axis, substantially as described.

15. In a friction device, a spring member consisting of a series of coils provided with flat bearing-surfaces at angles to the central axis of the device, and a frictional element consisting of a coiled spring engaging the said spring member and normally separated therefrom, the friction-surfaces of the frictional element being at angles to the aforesaid axis, substantially as described.

16. In a friction device, outer and inner coiled members which are normally separated, one of said members being flattened at its adjacent bearing-surfaces, and the outside diameter of the inner coiled member being greater than the inside diameter of the outer member, substantially as described.

In witness whereof I have hereunto signed my name this 17th day of December, 1903.

GEORGE LYON HARVEY.

In presence of- HOWARD SHAW, HAROLD CLINTON FENEE. 

